A typical capacitor has a pair of electrode layers with a dielectric material therebetween. Voltage is applied across the electrode layers in order to store a charge in the capacitor, with the amount of charge being storable in the capacitor, e.g. the capacitance, being proportional to the opposing areas of the electrodes and to the dielectric constant of the dielectric material. Capacitance has also been found to be inversely proportional to the thickness of the dielectric material, thus thin film capacitors are generally seen as a preferable means to achieve high capacitance. Problems still exist in optimizing the performance of these types of capacitors so there is a continuing need to improve electrical properties such as attaining higher dielectric constants, lowering the charge dissipation factors, and lowering the leakage currents.
A voltage variable capacitor, also known as a varactor, a variable capacitance diode or varacap, is a semiconductor device characterized by voltage sensitive capacitance which resides in the space charge region at the surface of a semiconductor bounded by an insulating layer. In order to form a high performance voltage variable capacitor a dielectric film having a very thin cross section and an extremely high integrity is required to be deposited on a semi conductive substrate. U.S. Pat. Nos. 5,192,871 and 5,390,072, incorporated herein by reference, describe the construction and use of semiconductor voltage variable capacitors. Although both of these patents suggest significant improvements in the art, a need still exists for making a voltage variable capacitor that does not rely upon the use of a semiconductive substrate. Clearly it would be an addition to the art if a capacitor could be realized that could have a variable capacitance and did not rely on a semiconductor.